Dark, darker yet darker memory
by SansationalTashaScribbles
Summary: Sans and Papyrus have hazy memories of their childhood. Sans has never really been bothered about it until certain events push him into looking into the mystery around the name W.D Gaster. Pre events of the Undertale game.
1. Prologue

Wobbly white blobs.

That was all he could see when he heard the name Gaster. It gave him a very strange feeling, unlike he had ever felt. A strange mix of safety yet disappointment and a little sadness. A sinking feeling of being let down. Sans had always found it very odd that this name made him feel like this. He had only read the name W.D. Gaster in history books. A genius who created the core. A former Royal Scientist. There were books written about his work, his theories and experiments but there was nothing about his personal life. Surely there were other monsters who had interacted with him. It seems most of his team had disappeared too. But surely the king must've known him. Asgore wouldn't say a word though.

Sans sighed and shut his book. This always happened recently. He was working on his PhD. He had always been very good at science and, with some encouragement from his younger brother, decided to do something with it. The king seemed oddly eager to have him in the royal labs, though Sans had no idea why. As far as he knew he had never met the king. Sans and Papyrus' past had always been somewhat of a mystery, even to Sans. Now for a long time, Sans hadn't cared much about it. It looked like too much effort to look into and both he and Papyrus were currently content. Sans put his head into his hands. Well, that wasn't quite true anymore. Since starting his studies, since studying Gaster, Sans had started seeing things, dreaming things, maybe even remembering things. And it was all pushing him into his past. Especially after a very confusing feeling of Déjà vu he had the first time he went to the core. His first port of call had been Grillbz, the monster who had basically been guardian to Sans and Papyrus until Sans was old enough for the responsibility. He had been with them as long as Sans could remember, so surely he would know something about what was happening to him. However when Sans asked him, he immediately went silent. As soon as he mentioned the name Gaster, Grillbz looked angry. Sans had barely mentioned any of the things he had been seeing before Grillbz snapped at him to stop and made it very clear he wouldn't say a thing on the subject.

That had been nearly a year ago and these dreams had only gotten worse, spilling into daydreams and seeing things while he was awake. And all Sans had to go on was wobbly images, sentence fragments and the name Doctor W.D. Gaster.


	2. Chapter 1

_-26 years earlier-_

Grillbz rushed through hotland to the royal lab as fast as he could. Gaster had sounded very scared. He had never heard the doctor sound so shaken. All sorts of scenarios were running through his head. Gasters work was often very experimental and dangerous. As the lab came into sight, Grillbz saw Gaster standing outside holding a bundle that, as he got closer, Grillbz identified as his lab coat. Apart from the very worried look on his face, Gaster seemed physically fine. Utterly confused, Grillbz waited for him to explain.

"My research into fabricating souls has taken quite an uh… interesting turn." Gaster looked down at the bundle in his arms. Grillbz took the hint and properly looked at the lab coat. At first he couldn't see anything. Then the coat moved a little bit. Grillbz looked a bit closer and realised the coat was staring back at him. He glanced back up at Gaster then looked back down to the little face watching him curiously. The whole monster in Gasters arms was so very tiny. Grillbz reached out to move the coat a little bit to get a better view. At the same time a tiny hand grabbed his extended hand. He watched as the small monster studied it for a second before trying to chew on a finger. It gave a little giggle then, satisfied the new person had been properly greeted, it snuggled back into the coat.

"Wingdings-?"

"I wanted to try putting a fabricated soul into a body. I thought it would strengthen it or something but…well I seem to have created a whole new uhm monster."  
Grillbz just stared at Gaster. He knew this is what happened. He could see that it had happened. And yet he couldn't quite believe what he was hearing. Gaster had literally created a new life in his lab.

"So Uh… what are you gonna do with…"

"Oh." Gaster realised he didn't have a name for… well he supposed he was his son. "Well him. I guess I'm gonna have to take him home and… take care of him I guess." Gaster thought about what this meant. He was a parent now. This wasn't just a soul he could leave at work. This was a living, breathing child. He then realised Grillbz was talking to him.

"Sorry. What?"

"I said where did the body even come from?"

Gaster shifted the bundle a little to show Grillbz his hand. It was bandaged across his palm.

"You… Used your own…?"

Gaster nodded.  
"Using a sample of my own genetic structure, I essentially grew a body."

Grillbz removed his glasses and wiped them with his shirt, giving himself time to understand the information he had just been given.

"Alright So now-?"

"Can you take him? Theres a few things I need to clear up here and the lab is too dangerous for a baby. And I guess I'll have to get things ready at home."  
Grillbz sighed and took the bundle. He wasn't that bad really, fast asleep hugging the arm of his fathers lab coat tightly. Grillbz took him home to wait for Gaster.

That became the norm.

Sans, as he was eventually named, seemed to spend more time with Grillbz. The most time Gaster spent with Sans was to make sure he was developing well. It wasn't that he minded having Sans, what annoyed Grillbz the most was that Gaster didn't seem too concerned about Sans. It was obvious Sans identified him as a parental figure, or at the very least, family. He would go to Gaster as soon as he saw him, only to be pushed back or taken away again. Of course Grillbz understood how important Gasters research was, how long and tiring the work could be and Gaster was obviously prioritising Sans' health and development as any parent would. But he was neglecting his emotional development and not quite bonding with him as he should be. And Sans couldn't understand any of this. He couldn't understand why his father left him for so long and was always usually too tired to do anything with him. Grillbz was okay, but Sans was literally a part of Gaster and they had a bond that Grillbz just couldn't replicate.

This also put too much of a strain on Gaster and Grillbz relationship. By the time Sans was a year old, he was the reason for the breakdown of their relationship, yet also the only reason they kept talking to each other. Despite what had happened, Grillbz couldn't leave Sans alone all those hours at his age. After all he was the only other one who really knew about the child. He also knew Sans was all Gaster had left that wasn't work, he couldn't get him taken away. And with their bond, Grillbz knew they had to stay together.

By the time Sans was two years old he was no longer a secret and had managed to win over everyone he met. This meant that others could step in to look after him sometimes. Which was just as well with the recent death of his father, Grillbz had become the sole owner of Grillbys and didn't have enough time to babysit. The king however, seemed to take quite a shine to the cheeky toddler. Just managing to walk, he was already creating trouble for everyone.  
At the age of four, Gaster realised his son was showing magical potential. This all came to a head one night when Sans managed to teleport from his own room to Gasters. When Gaster had gone to go to bed, he couldn't have been more confused. He was certain he had put Sans in in his own bed. After putting Sans in the correct bed, only to find him in his bed again, Gaster realised what was going on. It seemed his son had developed his ability to teleport. He would have to watch that one.

When he turned five, Sans, already getting quite good with his powers and rather good at creating mayhem with them, managed to access Gasters latest prototype, Weapon Experiment 265, later to be renamed the Gaster Blasters and, after the core, became one of Gasters greatest inventions. If he thought Sans got into trouble before then, the havoc he caused with the blasters was ten times worse. The only comforting thing was that it seemed he could only summon smaller blasters. So far the adult blasters only answered to Gaster.

Things took a terrifying turn when Sans was six. Gaster was called to the school urgently. When he got there, he was informed his son was inexplicably ill. At first it was feared he had fallen down, however, this illness was something no one had ever seen before. Of course there had never been anything like Sans created before, and Gaster would need to work fast to fix this. Gaster took him straight to the lab. It seemed as if his stats were dropping at an alarming rate. Not just his HP but his ATTK and DEF too. That was not good and highly unusual for a monster who had been perfectly healthy just hours before. He wouldn't survive into adulthood is his stats were too low, or even worse, he could turn to dust right now. Gaster worked through the night, creating medications, injections, connecting all sorts to his sons soul. Just when he was about to give up hope, when it looked like he was going to lose Sans forever, his Stats stuck. They didn't go up but they were no longer dropping. Something Gaster had done had worked. He would keep researching to see if there was a way to rebuild his stats.

Sans managed to recover well, back to his old self quite quickly. But his stats never did. Gaster couldn't find a fool proof way to tamper or test the Stats. At 1,1,1 Sans could not afford for an experiment to drop them anymore. They would have to stay like that for now. Because of this, Gaster became a little overprotective of Sans, keeping a closer eye on him, not letting him out as much and definitely not alone. There was a good side that came from all of this. Because the fright he had had, Gaster spent a lot more time with Sans, checking up on him a lot more than to just check he was growing. A proper bond was forming.  
Gaster also realised as part of his research into trying to stabilise Sans, Gaster had developed another soul. This gave him an idea. Another hole in his hand, this time a little more tampering, less magical ability, more drive, maybe a little more positivity.

A month later, Sans was introduced to Papyrus. At first he didn't really get along with him. Papyrus seemed to spend more time with Gaster than he ever did. Papyrus seemed to be cuter, more well behaved and everyones favourite. What Sans didn't realise Papyrus favourite person was him. This became apparent however, when the first proper word out of Papyrus' mouth was a kind of jumbled 'Sans', sounding more like Snaahs. Despite the incorrect pronunciation, Sans couldn't be happier. For a while he would only respond to Snas. From that point on, the brothers had an unbreakable bond.

When Sans was eight and Papyrus two, they were quite familiar with the lab in which Gaster worked in and the monsters he worked with. They would often sneak into and around the lab. Sans was becoming more interested in science, and Papyrus just did what Sans did. Gaster had told them countless times not to trespass into the labs. And one day, Sans wished he had done as his father had told him to. Unknown to the two brothers there was a human loose in the underground. Their favourite game to play in the lab was hide and seek. Of course Sans would usually let Papyrus win. This particular day, Sans was stood in a very obvious hiding spot, one he used a lot, it wouldn't take Papyrus long to find him. Which is why after ten minutes, Sans got a little worried. After all, Papyrus was very small still. Sans came out from behind the row of hanging lab coats to look for Papyrus, getting more and more worried. When he heard what was undeniably Papyrus screaming, it felt as if his chest was in a vice. He ran as quickly as he could in the direction of the sound. What he found was a strange looking thing, nothing like anything Sans had ever seen, towering over his baby brother. It's arm was raised, something in it's hand about to hit Papyrus. Sans did the first thing he thought of, put himself between Papyrus and the threat. Of course he didn't understand that Papyrus was actually stronger and more likely to survive the blow. Luckily for Sans, one of Gasters colleagues had what was about to happen and called Gaster down instantly. Gaster was nearly sick when he heard 'human' and 'your boys' in the same sentence. He slammed the phone down and teleported to the lobby where he had been told all of this was happening, just in time to send a Blaster to intercept the attack. There was a moment where no one was quite sure what was going on. It was broken by a tiny voice saying "Snahs?"Papyrus gently grabbed his brothers sleeve. With the spell broken, Gaster turned to his sons. Punishment would come later… as long as he could. He tried not to think about that.

"Sans, take your brother out of here."

Sans had never heard Gaster sound like that. He quickly picked up Papyrus and went into the next room. He held his brother tightly, not letting him see what was going on. However he kept an eye on the fight. Maybe he could help if Gaster got into any trouble.

"Attacking children. Pathetic." He heard his father say. There was a loud crack and a blinding flash, forcing Sans to look away. When he looked back, there was no human there anymore. Gaster was kneeling. And there was so much blood.

Gaster wasn't allowed to return to work for quite a few months. His face never healed, he would always have the cracks running through it.

Time seemed to fly by. Soon, Sans was twelve and Papyrus six and their lives were about to be completely turned upside down. With Papyrus able to spend time with friend and at others houses. Sans was now allowed into the labs at the weekend to assist Gaster. It was supposed to be an ordinary core check. Gaster had done it thousands of times. He was explaining to Sans all the things they had to check and why, what all the dials meant and how to check for broken or worn parts. Sans was so curious about the core. He had never been allowed in before. He was studying everything, taking it all in. Gaster was quite proud to see his son taking such an interest in his creation. While Gaster was explaining a certain part that helped reduce pressure, Sans was distracted by a part of the machinery, powered by what appeared to be lava. Leaving Gasters side, Sans went over, leaning against the rails to try and see as much as possible. The railings weren't used to being leaned on like Sans was doing and there was a creak and somewhere some nuts and bolts came loose. Gaster looked over wondering what that was. If something was loose or broken, he'd need to make a note of it. As he looked over he saw the railing Sans was leaning on, breaking. He dropped his clipboard and rushed over, grabbing Sans's arm, pulling him backwards, away from the drop. Sans felt himself hit the ground and looked up. As he did he saw Gaster fall forward, over the edge.

"Dad!"

Sans lurched forward, grabbing Gasters hand. He tried to pull him up. But he was only twelve. With no one else around and Sans was unable to leave to get anyone. Gaster knew what he had to do. He was going to pull Sans with him if he let this continue. He wriggled his hand until Sans lost his grip. Sans watched in horror, as his father fell. He tried grasping at air he tried to use his power but it was no use as Gaster literally disintegrated before his eyes.

And just like that he was gone.

One of Gasters colleagues found Sans till kneeling by the broken railing hours later. How was he going to explain this to Papyrus?

As predicted, Papyrus was a mess. Sans was just numb. He couldn't digest what had happened. It felt unreal, like a dream he was about to wake up from. That was when the nightmares started.

Over time the brothers forgot Gaster. Papyrus just accepted Sans was the one who raised him, that they had no parents. Sans, unable to cope with seeing his father die because of him, blocked it in his mind. He let himself believe Grillbz was their guardian until he was old enough to care for Papyrus.

And Sans would have been happy to keep believing that for the rest of his life.

Gaster however hadn't turned to dust, merely fragmented across the void. And he was getting ready to return.

He missed his boys.


End file.
